
attribute vec4 vertex;
uniform vec2 offset;
uniform vec2 scale;
varying vec2 tcoord;
void main(void) 
{
	vec4 pos = vertex;
	tcoord.xy = pos.xy;
    // -1, -1, 1,1 = 2
    vec2 toffset = vec2(-1,-1);
    vec2 tscale  = vec2(2,2);
    
	pos.xy = pos.xy*tscale+toffset;  
	gl_Position = pos;
}
